Hot Car Timer – How Hot Does a Car Get for a Dog?
Move the slider and watch how fast a parked car turns into an oven. There is no safe length of time.
Seen a dog in distress in a car? Ring 999 and ask for the police
The RSPCA has no legal power to enter a vehicle – only the police can. If a dog is showing any sign of heatstroke, 999 comes first.
There is no safe time to leave a dog in a warm car. Cracked windows and parking in the shade don't make it safe.
After 20 minutes
34°C
12°C above the 22°C outside, on a sunny day.
- 5 minutes
- 26°C
- 10 minutes
- 30°C
- 20 minutes
- 34°C
- 30 minutes
- 38°C
- 60 minutes
- 48°C
At 22°C outside, a car can reach 47°C within an hour.
If you see a dog in a hot car
- Any sign of heatstroke – ring 999 and ask for the police. Heavy panting, excessive drooling, lethargy, lack of coordination, vomiting or collapse.
- Stay with the dog and note the registration number.
- Ask nearby shops or the venue to make a tannoy announcement.
- England and Wales: RSPCA cruelty line 0300 1234 999 for advice. Scotland: Scottish SPCA. Northern Ireland: USPCA. The RSPCA cannot enter a vehicle – only the police can.
- Breaking a window could be criminal damage: tell the police what you intend and why, film and photograph everything, and take witness details.
Heatstroke is an emergency – act straight away
Signs to look for
- Heavy, frantic panting that does not settle
- Excessive drooling, very red or very pale gums
- Wobbliness, confusion or lack of coordination
- Vomiting or diarrhoea, sometimes with blood
- Lethargy, collapse, seizures or unconsciousness
Cool first, transport second
- Stop all activity and move your dog into shade or a cool room.
- Pour or spray cool water – not ice-cold – over them continuously, especially the neck, tummy and inside the back legs.
- Keep air moving over the wet coat with a fan, a breeze or an open car window.
- Offer small amounts of cool water to drink if they are fully conscious.
- Ring your vet immediately and tell them you are on your way.
Do not cover your dog with a wet towel and leave it on – it traps heat. Never use ice baths, which can cause the blood vessels in the skin to close and slow cooling down. Dogs can still be in serious trouble after they look better, so they always need a vet check.
How fast a parked car heats up
A car in the sun behaves like a greenhouse: sunlight passes through the glass, warms the seats and dashboard, and the heat cannot escape. The rise is fastest at the start – roughly eighty per cent of it happens in the first half an hour. Typical figures are about four degrees above the outside air after five minutes, eight after ten, twelve after twenty, sixteen after half an hour and twenty-six after an hour. The RSPCA's often-quoted example says it plainly: at twenty-two degrees outside, a car can reach forty-seven degrees within an hour.
Why the usual precautions do not work
Leaving the windows open a crack has been measured repeatedly and makes almost no difference to the peak temperature. Parking in the shade helps for a while, until the sun moves – which it does faster than most people expect. A bowl of water does not cool the air. Dogs cannot sweat; they rely on panting, and panting stops working once the air inside the car is hotter than they are. A dog can suffer irreversible organ damage in fifteen minutes.
What to do if you see a dog in a hot car in the UK
- Any sign of heatstroke – ring 999 and ask for the police. Heavy panting, excessive drooling, lethargy, lack of coordination, vomiting or collapse all count.
- If the dog seems well, note the registration, and ask nearby shops, the venue or the car park office to make an announcement over the tannoy. Stay with the car.
- For advice in England and Wales, ring the RSPCA cruelty line on 0300 1234 999. In Scotland contact the Scottish SPCA; in Northern Ireland, the USPCA. In a genuine emergency, 999 always comes first.
- Breaking a window could be classed as criminal damage. If you believe it is necessary, tell the police what you intend to do and why, photograph and film the situation, and take the names and numbers of witnesses.
- Once the dog is out, move them somewhere cool and shaded and start cooling with cool – not ice-cold – water while someone rings a vet.
It is not just cars
Caravans, vans, conservatories, sheds and outbuildings all heat up the same way. Dogs left in the boot of an estate car with the seats up are at particular risk, because there is less air and almost no ventilation.
Help us spread the word
Print the free A4 poster and put it up in your shop window, waiting room, village hall or car park. Every summer, the dogs that survive are usually the ones a passer-by noticed early.
Frequently asked questions
How hot does a car get in the sun?
Much faster than most people expect. A car parked in the sun is typically about 8°C above the outside air after ten minutes, 16°C after half an hour and 26°C after an hour. At 22°C outside, the RSPCA says a car can reach 47°C within an hour.
Is it safe to leave a dog in a car with the windows cracked?
No. Opening the windows a little makes almost no difference to how quickly the inside heats up, and neither does parking in the shade, because the sun moves. There is no safe length of time.
What if I'm only nipping into a shop for five minutes?
Five minutes routinely becomes twenty in a queue. Dogs have died in that time. Take your dog with you, leave them at home, or shop somewhere that lets dogs in.
What should I do if I see a dog in a hot car?
If the dog shows any sign of heatstroke – heavy panting, drooling, lethargy, lack of coordination, vomiting or collapse – call 999 and ask for the police. The RSPCA has no power to enter a vehicle; only the police do.
Can I break the window?
It may be classed as criminal damage. Tell the police what you intend to do and why, take photos and video, and get the names and numbers of witnesses before acting.
Who do I call outside England and Wales?
In Scotland contact the Scottish SPCA on 03000 999 999 and in Northern Ireland the USPCA on 028 3025 1000. In an emergency anywhere in the UK, ring 999 first.
Are vans and caravans safer?
No – vans, caravans, conservatories and outbuildings all heat up the same way, and dogs left in the boot of an estate car are at particular risk.
Estimates only – not a substitute for advice from your vet.
Last reviewed: 22 September 2026